You're right. In a convention setting I would say that this could be problematic.
With a close gaming group, like the one I'm a member of either at the club or at each others houses, we normally have games of 3-5 players each with a brigade, games lasting up to four hours.
Generally whoever is organising knows everyone and their playing styles so tries to fit the scenario, brigades and terrain to suit.
Players know each other well so during any down time, such as when a command is Hesitant, or just not very active, they are quite happy to watch each others misfortunes, with 'useful advice', check the rules etc.
However, players who aren't familiar with each other might get a little isolated. This isn't due to the rules necessarily. It seems to happen with most rule sets and is largely dependent on the character and personalities of players. At a convention this is difficult due to the 'sign up for a game' system as the organiser is unlikely to know everyone and their whims. A game is only as good as the participants. Plus, I get the feeling that some participants at a Con might not get the opportunity to play that often so the pressure is on the organiser to deliver.
Generally, in the UK at any rate, where there is an oft active club scene, or regular gaming groups, a great many people get to play very regularly so the odd inevitable bum game is much more forgivable.
Sorry. Probably not very helpful, but a few observations.